There has been a paucity of research concerning the functional state of the hypothalamic-pituitary-gonadal (HPG) axis in affective illness. With the recent availability of sensitive and accurate hormonal assays, new research methods have developed for studying functional alterations in hypothalamic-pituitary axes. Changes in sexual behavior and libido are common in patients with depression and mania, lending support to the need to examine functional state of the HPG axis in affective disease. The recent availability of synthetic gonadotropin-releasing hormone (GnRH) makes the proposed studies timely and feasible. The hypotheses proposed here are partly derived from findings of abnormalities in the hypothalamic-pituitary-adrenal and thyroid systems in some depressed patients. The objective of Study 1 is to identify functional alteration in the HPG axis of patients suffering primary affective illness by use of a bolus of GnRH. Alterations have been identified in other neuroendocrine axes of such patients, and it is possible that there are changes in this system. Study 2 expands upon the previous experiment by examining the hormonal response to a prolonged infusion of GnRH, which exposes the HPG axis to maximal stimulation of releasing hormone, revealing functional changes not observable by the single bolus method. For example, the constant infusion technique is more likely to identify alterations in testosterone production. Age- and sex-matched normal and psychiatric control groups will be studied in the same manner. Additionally, these pilot studies will examine the responses of several hormones to GnRH infusion, as the pattern of endocrine abnormalities may be more revealing than the isolated finding of altered gonadotropin response in depression.